The conversation about Teach
for America (TFA) has been reignited by a new study by Mathematica Policy
Research last week, which concludes that TFA teachers were more effective in
teaching secondary math than their peers who entered teaching from traditional
routes or from alternative teaching programs. The study focused on secondary math
because this it is an area experiencing teacher shortages. Mathematica evaluated the effectiveness of Teach for America and Teaching Fellows (an alternative teaching fellowship program) teachers and found that “[o]n average, students assigned to TFA teachers scored 0.07 standard deviations higher on end-of-year math assessments than students assigned to comparison teachers,” an impact “equivalent to an additional 2.6
months of school for the average student nationwide.” The study found no
significant difference between Teaching Fellows and traditional
teachers in secondary math assessments. The report, The Effectiveness of
Secondary Math Teachers from Teach For America and the Teaching Fellows
Programs, was sponsored by the Institute of Education Sciences, the research
arm of the Department of Education, and is available here.

Below is Mathematica's video presentation of the study's findings:

Articles about the study in
the Washington Post note that the Teach for America
program is deeply divisive, and as shown by the different takes in the Post hailing the results here and advising caution about interpreting the study here. The latter summarizes a post in Cloaking Inequity, which
challenges some of the Mathematica report's findings. In the
post, New Mathematica Study is Irrational Exuberance, Professor Julian Vasquez Heilig points
out that the study’s sample only contains secondary
math teachers when in most communities, the majority of TFA teachers teach
in elementary, not secondary schools. Because relatively few of
TFA teachers teach secondary math, Heilig argues that the study does not give a
balanced view of TFA or allow a solid conclusion to be made about comparisons
between TFA and experienced teachers. But that is what the Mathematica report seems to conclude in
this excerpt from the executive summary:

The study findings can provide
guidance to school principals considering hiring decisions. Although a specific
teacher from TFA or a Teaching Fellows program might be more or less effective
than a teacher from a traditional or less selective alternative route, our
findings can shed light on the average effectiveness of the teachers from TFA
relative to teachers from another route and on the average effectiveness of
Teaching Fellows relative to teachers from another route.

Our study suggests that, on average, principals of the secondary
schools in the study would raise student math achievement by hiring a TFA
teacher rather than a teacher from a traditional or less selective alternative
route to teach the math classes examined in the study.